[DebugInfo] Follow up to ee3eee71e, x86 tests need an x86 triple

llvm/test/DebugInfo/MIR/InstrRef/memory-operand-folding-tieddef.mir

@@ -1,5 +1,6 @@
 # RUN: llc %s -o - -experimental-debug-variable-locations \
 # RUN:    -start-before=x86-flags-copy-lowering -stop-after=virtregrewriter \
+# RUN:    -mtriple x86_64-unknown-unknown \
 # RUN: | FileCheck %s
 #
 # This test is for stack spill folding -- the INC32r near the end of the MIR

llvm/test/DebugInfo/MIR/InstrRef/memory-operand-folding.mir

@@ -1,5 +1,6 @@
 # RUN: llc %s -o - -experimental-debug-variable-locations \
 # RUN:    -start-before=x86-flags-copy-lowering -stop-after=virtregrewriter \
+# RUN:    -mtriple x86_64-unknown-unknown \
 # RUN: | FileCheck %s
 #
 # This test is for stack spill folding -- the SETCC near the start of the MIR

llvm/test/DebugInfo/MIR/InstrRef/memory-operand-load-folding.mir

@@ -1,5 +1,6 @@
 # RUN: llc %s -o - -experimental-debug-variable-locations \
 # RUN:     -start-before=phi-node-elimination -stop-after=virtregrewriter \
+# RUN:    -mtriple x86_64-unknown-unknown \
 # RUN:  | FileCheck %s
 #
 # Test that when a load gets folded into an instruction (the CVTTSS2SIrr below)

llvm/test/DebugInfo/MIR/InstrRef/memory-operand-tracking.mir

@@ -1,4 +1,7 @@
-# RUN: llc %s -march=x86-64 -run-pass=livedebugvalues -experimental-debug-variable-locations -o - 2>&1 | FileCheck %s
+# RUN: llc %s -march=x86-64 -run-pass=livedebugvalues \
+# RUN:      -mtriple x86_64-unknown-unknown \
+# RUN:      -experimental-debug-variable-locations -o - 2>&1 \
+# RUN: | FileCheck %s
 #
 # Test that memory operands of instructions are interpreted by LiveDebugValues:
 # if an instruction reference is substituted to a memory operand, we should be